Heat Exchanger

ABSTRACT

A heat exchanger plate for the use in a three circuit heat exchanger assembly, where the plate comprises a first distribution area, a heat exchange area and a second distribution area, where the plate comprises a corrugated pattern having ridges and valleys, and where the central port hole in the first distribution area is positioned at a vertical distance from the short end of the plate such that a fluid passage is obtainable between the central port hole and the short end of the plate when two plates are stacked to form a fluid channel between the plates. The invention further relates to an assembly made from such heat exchanger plates and a heat exchanger comprising a plurality of such assemblies. The advantage of the invention is that an improved heat exchanger is provided, having an increased thermal performance and an improved flow distribution in the heat exchanger.

TECHNICAL FIELD

The present invention relates to a plate heat exchanger having threeseparate fluid circuits. Such a plate heat exchanger will have twoindependent refrigerant circuits and one liquid circuit.

BACKGROUND ART

Plate heat exchangers having three separate fluid circuits, one circuitfor the liquid and two circuits for the refrigerant, show someadvantages with respect to heat exchangers having two fluid circuits.Such a heat exchanger allows for a well balanced cooling effect withless risk of freezing when used as an evaporator. It will also operateunder partial load conditions in an efficient way which will reduceenergy consumption. The installation will be easier and faster, whichwill reduce installation cost. Further, it will allow for a simpler andthus less expensive control system.

One common use of three circuit heat exchangers is as evaporators forevaporation of refrigerants flowing in refrigeration systems. Such arefrigeration system normally includes a compressor, a condenser, anexpansion valve and an evaporator. A plate heat exchanger used as anevaporator in a system of this kind often has heat exchanging platesthat are welded or brazed together, but also sealing gaskets may be usedfor sealing between the heat transferring plates.

EP 0765461 B shows a plate heat exchanger with flow passages for threedifferent fluids between the plates. The delivery of the three fluids tothe core of plates is done in such a way that passages for the fluidnumber one are present on both sides of every passage for each one ofthe two remaining fluids. The passages are created using two differentkinds of plates. Good sealing between adjacent plates at the openingscreating the inlet and outlet channels for the three fluids is createdby designing the areas around the ports, thereby defining a system withannular planar plateaus.

EP 1062472 B shows another example of a three fluid circuit heatexchanger. This application mainly concerns the connection of the portholes in an airtight manner.

EP 0965025 B describes a plate heat exchanger for three heat exchangingfluids. The port holes of the heat exchanger are pair wise aimed for theflowing through of the respective heat exchanging fluids and the portholes are symmetrically positioned on both sides of a heat transferringpart in such a way that a straight line drawn between the centres of theport holes divides the heat transferring part into two alike parts.

These heat exchangers will function perfectly well in some applications.Still, in the present heat exchangers, there is room for improvements.

DISCLOSURE OF INVENTION

An object of the invention is therefore to provide an improved heatexchanger having an improved flow distribution in each flow circuit. Afurther object of the invention is to provide a heat exchanger having animproved heat transfer coefficient.

The solution to the problem according to the invention is described inthe characterizing part of claim 1. Claims 2 to 11 contain advantageousembodiments of the heat exchanger plate. Claims 12 to 21 containadvantageous embodiments of a heat exchanger assembly. Claim 22 containsan advantageous heat exchanger.

With a heat exchanger plate for the use in a three circuit heatexchanger assembly, where the plate comprises a first distribution areahaving three port holes, a heat exchange area and a second distributionarea having three port holes, where the plate comprises a corrugatedpattern having ridges and valleys, the object of the invention isachieved in that the central port hole of the first distribution area ispositioned at a vertical distance from the short end of the plate suchthat a fluid passage is obtainable between the central port hole and theshort end of the plate when two plates are stacked to form a fluidchannel between the plates.

By this first embodiment of the plate for a heat exchanger assembly, aheat exchanger plate is obtained which allows for an improved flowdistribution in the first distribution passage for the refrigerantcircuits. The advantage of this is that a larger part of the heatexchanger plate, i.e. the area around the passive inlet port, can alsobe used as an effective heat transfer surface. Another advantage is thatthe flow distribution of the fluid in the first or lower distributionpassage is improved, which in turn improves the flow distribution in theheat transfer passage. Another advantage is that the flow in the liquidcircuit and into the liquid outlet port is also improved. The efficiencyof the heat exchanger will thus be improved.

In an advantageous development of the inventive plate, the central porthole of the second distribution area is positioned at a verticaldistance from the short end of the plate such that a fluid passage isobtainable between the central port hole and the short end of the platewhen two plates are stacked to form a fluid channel between the plates.The advantage of this is that a larger part of the heat exchanger plate,i.e. the area around the passive outlet port, can also be used as aneffective heat transfer surface. Another advantage is that the flowdistribution of the liquid from the inlet port is improved, which inturn improves the liquid flow distribution in the heat transfer passage.The efficiency of the heat exchanger will thus be further improved.

In an advantageous development of the inventive plate, at least onecorner of the plate is provided with a flat, ring-shaped bypass sectionadapted to form a refrigerant bypass passage around a port when twoplates are stacked to form a refrigerant fluid channel between theplates. This will improve the fluid distribution in the refrigerantchannels of the heat exchanger.

In an advantageous development of the inventive plate, at least onewater bypass section is provided at a corner of the plate such that awater passage is obtainable between two adjacent bypass sections whentwo plates are stacked to form a water channel between the plates. Thiswill improve the fluid distribution in the water channel of the heatexchanger.

In further advantageous developments of the inventive plate, a lowerdistribution groove is provided between the first distribution area andthe heat exchange area, the lower distribution groove comprises at leastone restriction area, and an upper distribution groove is providedbetween the heat exchange area and the upper distribution area. Allthese developments will allow for an improved fluid distribution in aheat exchanger.

In an advantageous development of the inventive plate, the firstdistribution area exhibits a chevron shape having a first layout, thesecond distribution area exhibits a chevron shape having a second layoutand where the heat exchange area exhibits a chevron shape having a thirdlayout, where the chevron shape of the first layout is directed in afirst angular direction and the chevron shape of the second layout isdirected in the opposite angular direction. This will allow for animproved heat transfer of the heat exchanger.

With a heat exchanger assembly, comprising four inventive heat exchangerplates, the object of the invention is achieved in that the first plate,the second plate, the third plate and the fourth plate are different.

In an advantageous development of the inventive assembly, where a firstrefrigerant channel is provided between the first plate and the secondplate, a water channel is provided between the second plate and thethird plate and a second refrigerant channel is provided between thethird plate and the fourth plate, and where each fluid channel comprisesa first distribution passage provided between two adjacent firstdistribution areas, a heat exchange passage provided between twoadjacent heat exchange areas and a second distribution passage providedbetween two adjacent second distribution areas, a horizontal passage isprovided in the first distribution passage between the central waterport and the short end of the assembly. This is advantageous in that thehorizontal passage will improve the flow distribution in the firstdistribution passage which in turn will improve the flow distribution inthe heat transfer passage. This will allow a larger part of the heatexchanger plate, i.e. the area around the passive inlet port, tofunction as an effective heat transfer surface. Another advantage isthat the fluid flow in the liquid circuit is improved since the completeliquid outlet port is open. The efficiency of the heat exchanger willthus be improved.

In an advantageous development of the inventive assembly, a horizontalpassage is provided in the second distribution passages between thecentral water port and the neighbouring short end of the assembly. Theadvantage of this is that a larger part of the heat exchanger plate,i.e. the area around the passive outlet port, can also be used as aneffective heat transfer surface. Another advantage is that the flowdistribution of the liquid from the inlet port is improved, which inturn improves the liquid flow distribution in the heat transfer passage.The efficiency of the heat exchanger will thus be further improved.

In an advantageous development of the inventive assembly, a water bypasspassage is provided in a water distribution passage between arefrigerant port and a corner of the assembly. This is advantageous inthat a water bypass is obtained, which will improve the water flowdistribution in the heat exchanger considerably.

In an advantageous development of the inventive assembly, a refrigerantbypass passage is provided around a refrigerant port in a refrigerantdistribution passage. This is advantageous in that the refrigerant flowdistribution is improved considerably.

In an advantageous development of the inventive assembly, the activerefrigerant inlet ports are provided with inlet nozzles, where the angleof the inlet nozzles is between 0 and 180 degrees relative a verticalaxis and where the inlet nozzle points towards the central vertical axisof the assembly. In this way, the inlet nozzle will point towards thecentre of the heat exchanger, which will improve the fluid distributionin the heat exchanger.

In an advantageous development of the inventive assembly, a lowerdistribution path is provided between a lower distribution passage and aheat exchange passage. This is advantageous in that the flowdistribution in the lower distribution passage can be controlled in amore refined way, such that the flow into the heat exchange passage canbecome as even as possible.

In an advantageous development of the inventive assembly, the lowerdistribution path comprises at least one restriction means such that aflow restriction is obtained in the lower distribution path. This isadvantageous in that the flow distribution in the lower distributionpassage can be controlled in a more refined way, such that the flow intothe heat exchange passage can be as even as possible.

In an advantageous development of the inventive assembly, an upperdistribution path is provided between the heat exchange passage and theupper distribution passage. This is advantageous in that the flowdistribution into the upper distribution passage can be evened outfurther.

In a three-circuit heat exchanger, comprising a plurality of inventiveheat exchanger assemblies and further comprising at least a front plateand a back plate, an improved heat exchanger is obtained.

BRIEF DESCRIPTION OF DRAWINGS

The invention will be described in greater detail in the following, withreference to the embodiments that are shown in the attached drawings, inwhich

FIG. 1 shows a heat exchanger plate assembly according to the invention,

FIG. 2 shows a first heat exchanger plate to be used in a heat exchangerplate assembly according to the invention,

FIG. 3 shows a second heat exchanger plate to be used in a heatexchanger plate assembly according to the invention,

FIG. 4 shows a third heat exchanger plate to be used in a heat exchangerplate assembly according to the invention, and

FIG. 5 shows a fourth heat exchanger plate to be used in a heatexchanger plate assembly according to the invention.

MODES FOR CARRYING OUT THE INVENTION

The embodiments of the invention with further developments described inthe following are to be regarded only as examples and are in no way tolimit the scope of the protection provided by the patent claims.

In the examples below, water is used as an example of a fluid that is tobe cooled or heated. The fluid that is to be cooled or heated is adaptedto be used in a single-phase, in a solely liquid state. The layout ofthe heat exchanger is thus adapted to a single-phase liquid for thewater circuit. It is of course possible to use other fluids as well,such as different mixtures of waters and other fluids, e.g. for thepurpose of anti-freezing or corrosion protection. A refrigerant is usedas an example of a fluid that is to be evaporated or condensed. Thisfluid will preferably be used in two phases, a liquid state and a vapourstate, but it is possible to use the fluid only in a single state,either in a liquid state, a vapour state or a mixture. The layout of theheat exchanger is thus adapted to a two-phase fluid for the other fluidcircuits.

The invention relates to a plate heat exchanger having three separatechannel types allowing for three different fluid flow circuits. One ofthe channels is adapted to carry a single-phase liquid that is to beheated or cooled. In this application, water will be used as an exampleof such a liquid. The other two channels are adapted to carry atwo-phase refrigerant that is adapted to evaporate or condensate in theheat exchanger. The channels may either be connected so that onerefrigerant is common to both circuits or the channels may be separatedso that a different refrigerant can be used in each circuit. In thisapplication, a two phase saturated fluid that is in a somewhatpressurized state when entering the heat exchanger and which willevaporate in the heat exchanger is used as an example of a refrigerant.

Further, the plate heat exchanger is in the described example of thepermanently joined type, i.e. the plates are brazed, glued, bonded,soldered or welded together to form a complete heat exchanger. The plateheat exchanger comprises a plurality of heat exchanger assemblies, whereeach assembly comprises four different heat exchanger plates. It ishowever also possible to use different sealing types, e.g. gasketsbetween the plates, welded plates or semi-welded plate unit with gasketsbetween every second plate.

The heat exchanger plates are formed using two different pressing tools,thereby obtaining two different plate types, a first plate type having achevron layout in one direction and a second plate type having a chevronlayout in the opposite direction. The layout comprises a corrugationpattern consisting of ridges and valleys which extend across the platesin a chevron layout with angle direction change points alonglongitudinal lines dividing the plate width into equal parts. Thecorrugation pattern together with the chevron layout is laid out such asto provide many crossing points of the pattern when the plates arestacked together, thereby creating a strong and rigid heat exchangerhaving a efficient heat transfer. Corrugated pattern and layouts of thiskind are well known to the skilled person. It is also possible to use acorrugated pattern having the same angle over the complete surface, i.e.which does not have any direction change points.

Each plate type is in a second operation run through one or more furtherpressing/cutting operations, thereby creating four different plates. Inthe further operations, the port hole regions of the plates are pressedand cut to the final shape and the nozzle indentation is formed.

The resulting plates, comprising a first plate 101, a second plate 201,a third plate 301 and a fourth plate 401, are stacked so that they forma heat exchanger plate assembly. The plates are stacked such that everyother plate is of the same plate type if the size and layout of the porthole region and the nozzle are not considered. The port hole regionswill differ between the plates, as will be described below. It is alsopossible to give the first and the second plate types different anglesof the chevron layout. The layout of the first plate type can thus havea slightly smaller angle and the layout of the second plate type aslightly larger angle, so that the mean value of the angles correspondsto the desired angle value of the layout.

Each heat exchanger plate comprises a first or lower distribution areacomprising three port holes, a central heat exchange area and a secondor upper distribution area comprising three port holes. Each plate has alongitudinal or vertical axis and a lateral or horizontal axis. The portholes of the first distribution area are arranged symmetrically withrespect to the longitudinal axis. The port holes of the seconddistribution area are also arranged symmetrically with respect to thelongitudinal axis. The port holes of the first and second distributionareas may be arranged symmetrically with respect to each other. In anadvantageous embodiment, the port holes of the first and seconddistribution areas are however not arranged symmetrically with respectto each other, since the port holes adapted for an evaporated phase of arefrigerant are larger in diameter than the port holes adapted for aflushed liquid vapour mixture of the refrigerant, and the port holes arepositioned at approximately the same distance from the corners of theplates. In this embodiment, the port holes in the second distributionarea are adapted for the refrigerant in the vapour state and the portholes in the first distribution area are adapted for the liquidrefrigerant.

The heat exchanger is in one example intended to be used for rising filmevaporation on the refrigerant channel side and cooling on the waterside in a counter-current flow arrangement. Below, a heat exchanger usedfor rising film evaporation will be used to exemplify the invention. Thereferences in the description will thus refer to the geometries for theposition of such a vertical, upright heat exchanger. It is also possibleto use the heat exchanger in other positions if required, e.g. atdifferent angles around the horizontal axis. The refrigerant two-phasefluid may be a mixture of liquid and vapour when entering the heatexchanger and may be completely evaporated, and even superheated, whenleaving the heat exchanger. The heat exchanger may also be used with thewater and the refrigerant flowing in the same directions, i.e. aco-current flow. The heat exchanger described is adapted for a diagonalflow of the refrigerant, i.e. the refrigerant will enter the heatexchanger through a port at a lower corner of the heat exchanger andwill leave the heat exchanger through a port in the opposite highercorner. It is of course also possible to adapt the heat exchanger for aparallel flow, where the refrigerant enters the heat exchanger through aport at a lower corner of the heat exchanger and leaves the heatexchanger through a port in the higher corner on the same side, byadapting the inlet or outlet ports accordingly.

The heat exchanger may also be used for falling film refrigerantcondensation while heating the water side in a counter-current flow orco-current flow arrangement. The two-phase refrigerant fluid may be in asuperheated or saturated vapour state when entering the heat exchangerthrough the upper distribution passage and may be partly or completelycondensed and even sub-cooled when leaving the heat exchanger throughthe lower refrigerant port. The heat exchanger may also be used as adesuperheater or gas cooler in a single phase heat transfer, or aneconomizer for evaporation, and similar uses, depending on therequirements of the installation. Small modifications may, depending onthe use, be required in the plate layout.

The first heat exchanger plate 101, shown in FIG. 2, comprises a firstor lower distribution area 102, a heat exchange area 103 and a second orupper distribution area 104. The plate has a longitudinal or verticalaxis 105 and a lateral or horizontal axis 106. The lower distributionarea 102 is provided with a first refrigerant inlet port hole 107, awater outlet port hole 112 and a second refrigerant inlet port hole 109.The first inlet port hole 107 is provided with a nozzle indentation 114.

It is to be understood that the complete surface of a heat exchangerplate, where there is a fluid passage on the other side of the plate, isa heat transfer area. The heat exchange area 103 is thus referred to asa heat exchange area since the main purpose is that of heat transfer,even though there will be some fluid distribution also in the heatexchange area. The lower and upper distribution areas have the dualpurpose of both fluid distribution as well as heat transferral.

The layout of the first distribution area 102 exhibits a single chevronshape, i.e. a V shape, where the direction change point is central tothe plate, dividing the first distribution area in two equal parts. Thelayout angle of the V layout is preferably between 50 and 70 degreeswith respect to the vertical axis of the heat exchanger. The interiorangle of the V shape is thus between 100 and 140 degrees. Other anglesare plausible but it is advantageous that the interior angle of the Vshape is obtuse. By giving the chevron layout a rather small angle inrelation to the horizontal axis, the friction factor in the horizontaldirection of the lower distribution channel will be relatively low,which will facilitate the distribution of the refrigerant over the platewidth.

The heat exchange area 103 is provided with a corrugated patternexhibiting a chevron layout, i.e. a W shape, having three directionchange points dividing the heat exchange area in four equal parts. Theinterior angle between the chevrons is of great importance for thefriction factor of a channel. For the same interior angle, one advantageof using a W shape instead of a V shape is that the mean friction factorfor the heat transfer area will be higher than when using a V shape. Theheat transfer coefficient will thus be higher than for a conventional Vshape. The use of the W shape gives a layout with three directionchanges. It is also possible to use a chevron layout having two, four oreven more direction changes. At the transition region of the chevrons,i.e. at the direction change points, the horizontal and also thevertical flow velocity component is reduced and may be close to zero. Inthe shown first plate, the layout resembles a W placed upside down.

The angle of the corrugated W shape is preferably between 50 and 70degrees with respect to the vertical axis of the heat exchanger. Theinterior angle of a chevron is thus between 100 and 140 degrees. Theinterior angle of the chevrons of the heat exchange area may be the sameas the chevrons of the first distribution area, or it may be somewhatsmaller. Other angles are plausible but it is important that theinterior angle of the chevrons is obtuse. The friction factor of theheat exchange passage depends e.g. on the interior angle of the chevronshape together with the number of direction changes.

The upper distribution area 104 of the plate is provided with a firstrefrigerant outlet port hole 108, a water inlet port hole 111 and asecond refrigerant outlet port hole 110. The corrugated pattern of theupper distribution area exhibits a chevron layout resembling a single Vplaced upside down. The interior angle of the V shape may be the same asfor the lower distribution area.

The interior angle of the chevrons in the lower distribution area, theheat exchange area and the upper distribution area may be the same orthe may differ. In an advantageous embodiment, the chevrons of the lowerdistribution area and the heat exchange area are provided with the sameinterior angle. The chevron shape of the upper distribution area is inthis embodiment provided with an angle that is smaller with respect tothe vertical axis. In a further advantageous embodiment, the chevrons ofthe lower distribution area is provided with a first angle, the chevronsof the heat exchange area are provided with a second, smaller angle andthe chevrons of the upper distribution area is provided with an evensmaller angle. Preferably, the angles are in the interval of between 50and 70 degrees. The advantage of having different interior angles of thedifferent areas is that, when the refrigerant is evaporating, the volumeflow will be higher in the upper part of the heat exchanger. Thedifferent interior angles will thus give a lower flow resistance whenthe volume flow increases with the flow direction in the channel. Thesame applies when the flow is opposite and the heat exchanger is used tocondense a vapour. A smaller interior chevron angle in relation to thevertical axis will give a lower flow resistance in this flow direction.

The second heat exchanger plate 201, shown in FIG. 3, comprises a lowerdistribution area 202, a heat exchange area 203 and an upperdistribution area 204. The plate has a vertical axis 205 and ahorizontal axis 206. The lower distribution area 202 is provided with afirst refrigerant inlet port hole 207, a water outlet port hole 212 anda second refrigerant inlet port hole 209. The first inlet port hole 207is provided with a nozzle indentation 214.

The layout of the lower distribution area 202 exhibits a single chevronshape, i.e. a V shape, where the V shape resembles a V placed upsidedown. The direction change point is central to the plate, dividing thefirst distribution area in two equal parts. Apart from the direction ofthe chevron shape, the angles of the layout are the same as for thefirst plate.

The heat exchange area 203 is provided with a corrugated patternexhibiting a chevron layout, i.e. a W shape, having three directionchange points dividing the heat exchange area in four equal parts. Inthe shown second plate, the layout resembles a W. Apart from thedirection of the chevron shape, the angles of the layout are the same asfor the first plate.

The upper distribution area 204 of the second plate is provided with afirst refrigerant outlet port hole 208, a water inlet port hole 211 anda second refrigerant outlet port hole 210. The corrugated cross patternof the upper distribution area exhibits a chevron layout resembling asingle V. The interior angle of the V shape may be the same as for thelower distribution area. Apart from the direction of the chevron shape,the angles of the layout are the same as for the first plate.

The third heat exchanger plate 301, shown in FIG. 4, comprises a lowerdistribution area 302, a heat exchange area 303 and an upperdistribution area 304. The plate has a vertical axis 305 and ahorizontal axis 306. The lower distribution area 302 is provided with afirst refrigerant inlet port hole 307, a water outlet port hole 312 anda second refrigerant inlet port hole 309. The upper distribution area304 of the plate is provided with a first refrigerant outlet port hole308, a water inlet port hole 311 and a second refrigerant outlet porthole 310. Apart from the port holes and the nozzle indentation, thethird heat exchanger plate resembles the first heat exchanger plate.

The fourth heat exchanger plate 401, shown in FIG. 5, comprises a lowerdistribution area 402, a heat exchange area 403 and an upperdistribution area 404. The plate has a vertical axis 405 and ahorizontal axis 406. The lower distribution area 402 is provided with afirst refrigerant inlet port hole 407, a water outlet port hole 412 anda second refrigerant inlet port hole 409. The upper distribution area404 of the plate is provided with a first refrigerant outlet port hole408, a water inlet port hole 411 and a second refrigerant outlet porthole 410. Apart from the port holes and the nozzle indentation, thefourth heat exchanger plate resembles the second heat exchanger plate.

In the description, the phrase active inlet port means that the inletport is open to let refrigerant flow through that inlet port into thatrefrigerant channel. A passive inlet port means that the inlet port issealed so that no refrigerant can flow into the refrigerant channelthrough the passive inlet port. The same applies for the phrase activeoutlet port, which means that the outlet port is in contact with therefrigerant channel so that the refrigerant flows out of the activeoutlet port. A passive outlet port is sealed so that no refrigerant canflow out from the refrigerant channel through the passive outlet port.

In FIG. 1, an inventive heat exchanger plate assembly 1 comprising afirst plate 101, a second plate 201, a third plate 301 and a fourthplate 401 is shown. The different plates are shown in FIGS. 2-5. Theplates are stacked on each other in the number required for a specificheat exchanger. In this way, a heat exchanger comprising a plurality ofassemblies is formed. The number of assemblies is selectable dependingon the required specifications of a heat exchanger. A complete heatexchanger will also include a specific front plate and back plate (notshown) having a larger thickness than the individual heat exchangerplates. The front plate and back plate will comprise connections etc. Ina complete heat exchanger, the liquid channel closest to the front andback plate will be a water channel. A separate heat exchanger plateforming a water channel with the first plate may thus be comprised inthe front plate, and a separate heat exchanger plate forming a waterchannel with the fourth plate may thus be comprised in the back plate.The front and back plates will strengthen the heat exchanger, making itmore stable and rigid.

The heat exchanger is of the brazed type. Between the first and thesecond plate, a first refrigerant channel 2 is formed. Between thesecond and the third plate, a water channel 3 is formed. Between thethird and the fourth plate, a second refrigerant channel 4 is formed.Between the fourth plate and the first plate of a further assembly, awater channel is formed. In this way, the heat exchanger will havealternating first and second refrigerant channels, being surrounded by awater channel on each side.

Both a refrigerant channel and a water channel will comprise a lowerdistribution passage, a heat exchange passage and an upper distributionpassage. The vertical length of the lower distribution passage ispreferably less than half of the width of the heat exchanger, while thevertical length of the upper distribution passage is preferably lessthan two thirds of the width of the heat exchanger.

When the first plate 101 and the second plate 201 are positioned next toeach other, a first refrigerant channel 2 is formed. The refrigerantwill enter the first refrigerant channel through a first refrigerantinlet port 21, being an active inlet port, created by the firstrefrigerant inlet port holes 107, 207. The inlet port holes 107, 207 areprovided with concentric sealing sections 113, 213 that will bear oneach other. The inlet into the first refrigerant channel is provided byan inlet nozzle 25 in the sealing sections. The inlet nozzle is obtainedby nozzle indentations 114, 214 in one or both of the sealing sections,pressed in the second press operation. The size of the inlet nozzle,i.e. the length and the cross section, together with the angularposition of the inlet nozzle are both important for the refrigerantdistribution in the lower distribution passage 10 created between thelower distribution areas 102 and 202. The size of the inlet nozzledepends partly on the inlet pressure of the refrigerant and is selectedto achieve an even flow distribution over all refrigerant channels in acomplete heat exchanger. The angular position of the inlet nozzle ischosen such that the refrigerant can distribute evenly over the totalwidth of the heat exchanger in each refrigerant channel.

The inlet nozzle may be directed in any chosen angle, depending e.g. onthe corrugated pattern layout in the lower distribution passage and thebypass section around the inlet port. Preferably, the angle of the inletnozzle is between 0 and 180 degrees relative a vertical axis andpointing towards the central vertical axis of the plate, and morepreferably between 90 and 150 degrees.

In one embodiment, the inlet port is opened. This may be advantageouswhen the heat exchanger is used such that the inlet port acts as avapour outlet port, e.g. in a gas cooler. In order to avoid vapour fromblocking the outlet, the sealing section and the nozzle are cut away inthe production stage. Instead, an open port, resembling outlet port 22,is obtained. Such a port will allow vapour or a mixture of vapour andliquid to exit through the port.

In order to improve the refrigerant distribution further, the activeinlet port is provided with an active inlet port bypass passage 18around the inlet port, allowing the refrigerant to flow around bothsides of the inlet port. Each plate comprises a bypass section 115, 215extending around the entire first inlet port hole. The bypass sectionhas the same pressing depth as the corrugations of the plate. Theresulting bypass passage 18 will thus have the height of two times thepressing depth, which means that the friction pressure drop in thebypass passage will be much smaller than through the corrugationpattern. The bypass passage 18 will thus distribute part of therefrigerant from the inlet nozzle to the distribution area around theactive inlet port.

Part of the refrigerant from the nozzle will also continue in thedirection from the nozzle into the corrugation pattern and furthertowards the second refrigerant inlet port 23, being a passive inletport. Since the water outlet port holes 112, 212 are positioned at avertical distance from the lower short end of the plate, a lowerhorizontal passage 13 is formed in the lower distribution channelbetween the water outlet port and the lower short end of the heatexchanger. The refrigerant can thus flow below the water outlet port andover to the region around the passive inlet port. The refrigerant flowout of the inlet nozzle has in this example approximately the same angleas the corrugation pattern of the first plate, so that part of therefrigerant can pass mainly in a horizontal direction below the wateroutlet port with a relatively small friction factor and thus at arelatively high flow rate. When the refrigerant reaches the regionaround the passive inlet port, a passive inlet port bypass passage 19around the passive inlet port will facilitate the distribution of therefrigerant to the area around the passive inlet port. The bypasspassage 19 around the passive inlet port 23 is created in the same wayas at the active inlet port, by each plate comprising a bypass section117, 217 extending around the entire second inlet port hole. The bypasssection has the same pressing depth as the corrugations of the plate.The resulting bypass passage will thus have the height of two times thepressing depth, which means that the friction in the bypass passage willbe much smaller than through the corrugation pattern. The bypass passagewill thus distribute part of the refrigerant to the distribution areaaround the passive inlet port. The second inlet port holes 109, 209 areprovided with concentric sealing sections 116, 216 that will bear oneach other and will thus seal off the passive inlet port.

The flat, circular section around the water outlet port holes 112, 212bear on each other so that the water outlet port is sealed to therefrigerant channel. The water outlet holes are positioned at a verticaldistance from the lower short end of each plate. A water outlet hole islarger in diameter than a refrigerant inlet port hole, and the centre ofa water outlet hole is positioned closer to the horizontal axis of aplate than the centre of the refrigerant inlet port holes. In this way,a lower horizontal passage 13 is created in the refrigerant channelbetween the water outlet port and the lower short end of the heatexchanger. Through this passage, the refrigerant can pass below thewater outlet port to the region around the passive inlet port. Thisconsiderably improves the distribution of refrigerant over the channelwidth, and gives a more uniform flow over the channel width and thusthrough the heat exchange passage. The passage below the water outletport will also increase the effective heat transfer area of the heatexchanger with the region around the passive inlet port.

In order to improve the distribution of the refrigerant further, thefirst refrigerant channel is provided with lower distribution paths 15,16 placed above the active and the passive inlet ports, between thelower distribution passage 10 and the heat exchange passage 11. Thelower distribution paths are created by mainly flat distribution grooves118, 119, 218, 219 pressed in the plates between the V shape of thedistribution area and the W shape of the heat exchange area, extendingfrom the long side of a plate to the water outlet port hole. The lowerdistribution paths will on one hand facilitate the distribution of therefrigerant uniformly into the heat exchange passage 11 and on the otherhand act as a transitional region for the V shaped layout of thedistribution area and the W shaped layout of the heat exchange area. Theheight of the lower distribution paths and also the shape may beselected in order to optimise the flow distribution. The height of apressed groove may in one example be approximately half the pressingdepth of a plate. To improve the mechanical strength of the heatexchanger, a lower distribution path may also comprise one or morecontact points. Since corresponding distribution paths will be createdin the water channel, the height of a lower distribution path in therefrigerant channel is preferably not more than a total of one pressingdepth. The lower distribution paths will have a low flow resistance inthe horizontal direction of the channel, compared to the flow resistancethrough a flow tube with the same length and width in the corrugatedpattern of the heat exchange passage.

If required, the lower distribution paths 15, 16 may comprise one ormore restriction areas in order to control the flow distribution overthe width of the channel in the lower distribution passage. The size andposition of the restriction areas are chosen such that the flow througha distribution path 15 or 16 is as evenly distributed as possible. Therestrictions may be achieved by altering the pressing depth of theposition of the restriction area in the plates, i.e. by altering theheight of the restriction area, and/or by altering the width of therestriction area along the lower distribution path. In this way,different restrictions may be positioned at different positions in thelower distribution paths 15, 16. The restrictions will give a locallyincreased flow resistance that will provide a flow distribution over thewidth of the lower distribution paths. In one example, the restrictionscover most of the distribution paths, thereby creating one or a fewsmall openings between the distribution passage and the heat exchangepassage. The size and positions of the restrictions may be decided on byexperiments or by calculations. The distribution of the refrigerantflowing into the heat exchange passage will thus be improved.

After entering the active inlet port 21 and being distributed in thelower distribution passage 10, the refrigerant will enter and pass theheat exchange passage 11 created between the heat exchange areas 103,203. The heat exchange passage, with all the contact points between thecorrugated patterns of the two plates, provides a large heat exchangearea and a relatively high friction flow resistance, which ensures anefficient heat transfer between the refrigerant and the water channels.The W shape increases the friction pressure drop somewhat in the heatexchange passage compared with a single V shape, which improves thetotal heat transfer of the heat exchanger.

Between the heat exchange area and the upper distribution area of eachplate a horizontal flat distribution groove 120, 220 is pressed in eachplate, creating an upper distribution path 17 in the first refrigerantchannel. The upper distribution path will allow the refrigerant flow todistribute and at the same time to even out the differences in pressure,that may arise in the heat exchange passage due to variations of theevaporation of the refrigerant, prior to entering the upper distributionpassage created between the upper distribution areas 104, 204 of theplates. The upper distribution path will have a low flow resistance inthe horizontal direction of the heat exchanger, which will facilitatethe distribution of the refrigerant before entering the upperdistribution passage 12. Mainly in the upper distribution passage, theevaporation of the refrigerant will be finalized and a superheating ofthe refrigerant vapour may also occur. The height of each distributiongroove is approximately half the pressing depth of a plate, since acorresponding horizontal distribution path will be created in the waterchannel. This will give the upper distribution path a total height ofone pressing depth.

The refrigerant, being to a large degree in an evaporated state, entersthe upper distribution passage created by the upper distribution areas104, 204 of the plates. The first refrigerant outlet port 22, being anactive port, is created between the plates at the first refrigerantoutlet port holes 108, 208. Part of the refrigerant will enter the upperdistribution passage on the right side of the vertical axis 105, andpart of the refrigerant will enter the upper distribution passage on theleft side of the vertical axis 105. Part of the refrigerant will reach abypass passage 20 created by bypass sections 121, 221 extending aroundthe entire second outlet port 24. The second refrigerant outlet portholes 110, 210 are provided with concentric sealing sections 122, 222that will bear on each other and seal the second outlet port 24, being apassive outlet port. A bypass section has the same pressing depth as thecorrugations of the plate. The resulting bypass passage 20 will thushave the height of two times the pressing depth, which means that theflow resistance in the bypass passage will be much smaller than throughthe corrugation pattern. The bypass passage will thus allow aconsiderable part of the refrigerant, which may be superheated, to passmainly horizontally over to the active outlet port via the horizontalpassage above the water inlet port.

The flat, circular section around the water inlet port holes 111, 211bear on each other so that the water inlet is sealed from therefrigerant channel. The water inlet port holes are positioned at avertical distance below the upper short end of each plate. The centre ofa water inlet hole is positioned closer to the horizontal axis of aplate than the centre of the refrigerant outlet port holes. In this way,an upper horizontal passage 14 is provided in the refrigerant channelbetween the water inlet port and the upper short end of the heatexchanger. Through this horizontal passage, the refrigerant can flowabove the water inlet port from the bypass passage 20 at the passiveoutlet port 24 to the active outlet port 22 formed between the firstrefrigerant outlet port holes 108, 208. This decreases the flowresistance for the vapour, which may be superheated, and improves theflow distribution in the upper distribution passage considerably.Further, this horizontal passage prevents vapour to cumulate around thepassive outlet port which would lead to an insulating area with vapourstanding still in the area around the passive outlet port. The passagewill also enlarge the total effective heat transfer area of the heatexchanger by the region around the passive outlet port.

When the second plate 201 and the third plate 301 are positioned next toeach other, a water channel 3 is created. The water will enter the waterchannel through the water inlet port 42 created by the water inlet portholes 211, 311. The water will leave the water channel through the wateroutlet port 43 created by the water outlet port holes 212, 312. All therefrigerant ports will be sealed so that the water and refrigerant willnot mix. When the second and third plates are stacked, the bypasssections 215, 315 will bear on each other and will thus seal the firstrefrigerant inlet port. The same applies for the bypass sections 217,317 and the bypass sections 221, 321 which will also bear on each otherso that the second refrigerant inlet port and the second refrigerantoutlet port are sealed. The first refrigerant outlet port is sealed bythe flat sections 223, 323 around the first refrigerant outlet portholes 208, 308 bearing on each other.

The water inlet holes 211, 311 are positioned at a vertical distancefrom the upper short end of each plate edge of each plate. The centre ofa water inlet hole is positioned closer to the horizontal axis of aplate than the centre of the refrigerant outlet port holes. In this way,an upper horizontal passage 34 is created in the water channel betweenthe water inlet port and the upper short end of the heat exchanger. Thisenlarges the useful water inlet cross flow area which in turn improvesthe water distribution in the upper distribution passage and decreasesthe pressure drop of the water channel.

In order to improve the water distribution further and also to decreasethe water pressure drop, the water channel is provided with upper waterbypass passages 40, 41 between the passive second and first refrigerantoutlet ports and the upper corners of the heat exchanger. The upperwater bypass passages 40, 41 are created by water bypass sections 226,227, 326, 327 outside each one of the second and first refrigerantoutlet port holes. These bypass sections bear on each other when theplates are positioned to create a refrigerant channel, which means thatthe water bypass passages will have a height of two times the pressingdepth. These water bypass passages will thus have a low frictionpressure drop and will considerably facilitate water side distributionover the entire upper distribution passage.

When the water is distributed in the upper distribution passage 32, thewater passes horizontal flat distribution grooves 220, 320 pressed ineach plate, creating an upper horizontal distribution path 37 in thewater channel. This distribution path allows for an additionaldistribution of the water so that the water pressure along the entireupper distribution path is substantially equal. The upper distributionpath also acts as the transitional region between the V shape of theupper distribution passage and the W shape of the heat exchange passage.The height of each distribution groove is approximately half thepressing depth of a plate. This will give the upper distribution path aheight of a total of one pressing depth.

After passing the upper distribution path 37, the water will enter andpass the heat exchange passage 31 created between the heat exchangeareas 203, 303. The heat exchange passage, with all the contact pointsbetween the corrugated patterns of the two plates, provides a large heatexchanger area and a relatively high friction factor, which ensures anefficient heat transfer between the water and the refrigerant channels.The W shaped layout increases the friction factor somewhat in the heatexchange passage in relation to a single V layout, which will improvethe heat transfer.

When the water has passed the heat exchange passage 31, it enters thelower distribution passage 30 through two lower distribution paths 35,36 positioned between the heat exchange passage and the lowerdistribution passage. These lower distribution paths are created bymainly flat distribution grooves 218, 219, 318, 319 pressed in theplates between the V shape of the distribution area and the W shape ofthe heat exchange area, extending from the long side of a plate to thewater outlet port hole. These distribution paths will both facilitate todistribute the water uniformly into the lower distribution passage andact as a transitional region for the W shaped layout of the heatexchange passage and the V shaped layout of the lower distributionpassage. The height of the lower distribution paths and also the shapemay be selected in order to optimise the flow distribution. The heightof a pressed groove may in one example be approximately half thepressing depth of a plate. To improve the mechanical strength of theheat exchanger, a lower distribution path may also comprise one or morecontact points. The distribution paths will have a low flow resistancein the horizontal direction of the heat exchanger, compared to the flowresistance through the corrugated pattern in the lower distributionpassage. This will facilitate an even flow distribution of the waterinto the lower distribution passage.

Some of the water, especially the water from the centre of the heatexchange passage 31, will enter the water outlet port 43 created by thewater outlet port holes 212, 312 directly from the heat exchange passageabove. Since the corrugated pattern around the water outlet port allowsfor a water flow from all directions into the water outlet port, thewater outlet port is fully open. This will allow for part of the waterdistributed to the lower distribution area to enter the water outletopening via the pattern between the water outlet port and therefrigerant inlet ports and also from the pattern below the water outletport.

In order to improve the water distribution further, the lowerdistribution passage 30 is provided with lower water bypass passages 38,39 between the passive first and second refrigerant inlet ports and thelower corners of the heat exchanger. The lower water bypass passages arecreated by water bypass sections 224, 225, 324, 325 at each one of thefirst and second refrigerant inlet port holes. These bypass sectionsbear on each other when the plates are positioned to create arefrigerant passage, which means that the lower water bypass passagewill have a height of two times the press depth. These lower waterbypass passages will thus have a low friction pressure drop and willcontribute considerably to the guiding of the water flow to the wateroutlet port.

In order to improve the water distribution and to enlarge the effectiveheat transfer area of the heat exchanger, the water outlet port holesare positioned at a vertical distance from the lower short end of eachplate. In this way, a lower horizontal passage 33 is created in thewater channel between the water outlet port and the lower short end ofthe heat exchanger. Through this horizontal passage, the water can flowinto the water outlet port also from below the port, improving theefficiency of the heat exchanger. The lower bypass passages togetherwith the upward offset of the water outlet port improve the outlet flowdistribution of water considerably and decreases the outlet pressuredrop all around the port periphery by enlarging the useful water crossflow area.

The second refrigerant channel 4 is created between the third plate 301and the fourth plate 401 when they are positioned next to each other andresembles the first refrigerant channel. The difference between thefirst refrigerant channel and the second refrigerant channel are onlythe inlet and outlet ports and the inlet nozzle.

The refrigerant will enter the second refrigerant channel through asecond refrigerant inlet port 63, being an active inlet port, created bythe refrigerant inlet port holes 309, 409. The inlet port holes 309, 409are provided with concentric sealing sections 316, 416 that will bear oneach other. The inlet into the second refrigerant channel is provided byan inlet nozzle 65 through the sealing sections. The inlet nozzle isobtained by nozzle indentation 314, 414 in one or both of the sealingsections. The size of the inlet nozzle, i.e. the length and the crosssection, together with the angular position of the inlet nozzle are bothimportant for the refrigerant distribution in the lower distributionpassage 50 created between the lower distribution areas 302 and 402. Thesize of the inlet nozzle is selected partly depending on the pressuredrop of the refrigerant circuit and is selected to obtain an even flowdistribution over all refrigerant channels in the refrigerant circuit ina complete heat exchanger. The angular position of the inlet nozzle ischosen such that the refrigerant can distribute evenly over the totalwidth of the heat exchanger in each refrigerant channel.

The inlet nozzle may be directed in any chosen angle, depending e.g. onthe corrugated pattern layout in the lower distribution passage and thebypass section around the inlet port. Preferably, the angle of the inletnozzle is between 0 and 180 degrees relative a vertical axis andpointing towards the central vertical axis of the plate, and morepreferably between 90 and 150 degrees.

In order to improve the refrigerant distribution further, the activeinlet port is provided with an active inlet bypass passage 59 around theinlet port, allowing the refrigerant to flow around both sides of theinlet port. Each plate comprises a bypass section 317, 417 extendingaround the entire inlet port hole. The bypass section has the samepressing depth as the corrugations of the plate. The resulting activeinlet bypass passage will thus have the height of two times the pressingdepth, which means that the friction in the bypass passage will be muchsmaller than through the corrugation pattern. The bypass passage willthus distribute part of the refrigerant from the inlet nozzle to thedistribution area around the active inlet port.

Part of the refrigerant from the nozzle will also continue in thedirection from the nozzle into the corrugation pattern in the directiontowards the first refrigerant inlet port 61, being a passive inlet port.Since the water outlet port holes 312, 412 are positioned at a verticaldistance from the lower short end of each plate, a lower horizontalpassage 53 is formed in the lower distribution channel between the wateroutlet port and the lower short end of the heat exchanger. Therefrigerant can thus flow below the water outlet port to the regionaround the passive inlet port. The refrigerant flow out of the inletnozzle has in this example approximately the same angle as thecorrugation pattern of the third plate, so that part of the refrigerantcan pass mainly in a horizontal direction below the water outlet portwith a relatively small friction factor and thus a relatively high flowrate. When the refrigerant reaches the region around the passive inletport 61, a bypass passage 58 around the passive inlet port will helpdistribute the refrigerant to the area around the passive inlet port.The bypass passage 58 is created in the same way as at the active inletport, by each plate comprising a bypass section 315, 415 extendingaround the entire first refrigerant inlet port hole. A bypass sectionhas the same pressing depth as the corrugations of the plate. Theresulting bypass passage will thus have the height of two times thepressing depth, which means that the friction in the bypass passage willbe much smaller than through the corrugation pattern. The bypass passagewill thus distribute part of the refrigerant to the distribution areaaround the passive inlet port. The first inlet port holes 307, 407 areprovided with concentric sealing sections 313, 413 that will bear oneach other and will thus seal off the passive inlet port.

The flat, circular section around the water outlet port holes 312, 412bear on each other so that the water outlet port is sealed to therefrigerant channel. The water outlet port holes are positioned at avertical distance from the lower short end of each plate. A water outlethole is larger in diameter than a refrigerant inlet port hole, and thecentre of a water outlet hole is positioned closer to the horizontalaxis of a plate than the centre of the refrigerant inlet port holes. Inthis way, a lower horizontal passage 53 is created in the refrigerantchannel between the water outlet port and the lower short end of theheat exchanger. Through this horizontal passage, the refrigerant canpass below the water outlet port to the region around the passive inletport. This improves the distribution of refrigerant considerably overthe plate width, which gives a more uniform flow through the heatexchange passage and also enlarges the total effective heat transferarea of the heat exchanger with the region around the passive inletport.

In order to enhance the distribution of the refrigerant further, thesecond refrigerant channel is provided with lower distribution paths 55,56 placed above the passive and the active inlet ports, between thelower distribution passage 50 and the heat exchange passage 51. Thelower distribution paths are created by mainly flat distribution grooves318, 319, 418, 419 in the plates between the V shape of the distributionarea and the W shape of the heat exchange area, extending from the longside of a plate to the water outlet port hole. The lower distributionpaths will on the one hand facilitate the uniform distribution of therefrigerant into the heat exchange passage 51 and on the other hand actas a transitional region for the V shaped layout of the distributionarea and the W shaped layout of the heat exchange area. The height ofthe lower distribution paths and also the shape may be selected in orderto optimise the flow distribution. The height of a groove may in oneexample be approximately half the pressing depth of a plate. To improvethe mechanical strength of the heat exchanger, the lower distributionpath may also comprise one or more contact points. Since correspondingdistribution paths will be created in the water channel, the height of alower distribution path in the refrigerant channel is preferably notmore than a total of one pressing depth. The lower distribution pathswill have a low flow resistance in the horizontal direction of the heatexchanger, compared to the flow resistance through a flow tube with thesame length and width in the corrugated pattern of the heat exchangepassage. The lower distribution paths 55, 56 may also comprise one ormore restriction areas in order to control the flow distribution overthe channel width in the lower distribution passage. The restrictionsmay be fairly small, resembling one or more contact points, or they maybe relatively large, such that only one or a few small passages arecreated between the distribution passage and the heat exchange passage.

After entering the active inlet port 63 and being distributed in thelower distribution passage 50, the refrigerant will enter and pass theheat exchange passage 51 in the same way as described for the firstrefrigerant channel.

Between the heat exchange area and the upper distribution area of eachplate is a horizontal flat distribution groove 320, 420 pressed in eachplate, creating an upper distribution path 57 in the second refrigerantchannel. The upper distribution path will allow the differences inpressure that may arise in the heat exchange passage due to variationsof the evaporation of the refrigerant to even out before the refrigerantenters the upper distribution passage 52 created between the upperdistribution areas 304, 404 of the plates. The refrigerant may at thisstage be partly or fully evaporated, and may even be superheated. Theupper distribution path will have a low flow resistance in thehorizontal direction of the heat exchanger, which will facilitate thedistribution of the refrigerant before entering the upper distributionpassage. The height of each distribution path is approximately half thepressing depth of a plate, since a corresponding horizontal distributionpath will be created in the water channel. This will give thedistribution path a height of a total of one pressing depth.

The refrigerant, being in this cross section to a large degree in vapourform, enters the upper distribution passage 52 created by the upperdistribution areas 304, 404 of the plates. The second refrigerant outletport 64, being an active port, is created between the plates at thesecond refrigerant outlet port holes 310, 410. Part of the refrigerantwill enter the upper distribution passage on the left side of thevertical axis 305, and part of the refrigerant will enter the upperdistribution passage on the right side of the vertical axis 305. Part ofthe refrigerant will reach a passive outlet port bypass passage 60created by bypass sections 323, 423 extending around the entire firstrefrigerant outlet port 62, being a passive outlet port. The firstrefrigerant outlet port holes 308, 408 are provided with concentricsealing sections 328, 428 that will bear on each other and seal thefirst outlet port. A bypass section has the same pressing depth as thecorrugations of the plate. The resulting bypass passage will thus havethe height of two times the pressing depth, which means that thefriction in the bypass passage will be much smaller than through thecorrugation pattern. The bypass passage will thus allow a considerablepart of the refrigerant, which may be superheated, to pass over to theactive outlet port via the cross corrugation pattern passage above thewater inlet port.

The flat, circular section around the water inlet port holes 311, 411bear on each other so that the water inlet is sealed from therefrigerant channel. The water inlet port holes are positioned at avertical distance from the upper short end of each plate. The centre ofa water inlet hole is positioned closer to the horizontal axis of aplate than the centre of the refrigerant outlet port holes. In this way,an upper horizontal passage 54 is provided in the refrigerant channelbetween the water inlet port and the upper short end of the heatexchanger. Through this horizontal passage, the refrigerant can flowabove the water inlet port from the bypass passage 60 at the passiveoutlet port 62 to the active outlet port 64 formed between the secondrefrigerant outlet port holes 310, 410. This improves the flowdistribution of refrigerant considerably in the upper distributionpassage and prevents heat congestion around the passive outlet port.Further, the total effective heat transfer area of the heat exchanger isenlarged by the region around the passive outlet port.

By the invention, an improved three-circuit plate heat exchanger can beobtained, which shows a considerable improvement in the overall thermalperformance of the heat exchanger. This is due to the improved flowdistribution in the heat exchanger. The invention is not to be regardedas being limited to the embodiments described above, a number ofadditional variants and modifications being possible within the scope ofthe subsequent patent claims.

REFERENCE SIGNS

1: Plate assembly

2: First refrigerant channel

3: Water channel

4: Second refrigerant channel

10: Lower distribution passage

11: Heat exchange passage

12: Upper distribution passage

13: Lower horizontal passage

14: Upper horizontal passage

15: Lower distribution path

16: Lower distribution path

17: Upper distribution path

18: First refrigerant inlet port bypass passage

19: Second refrigerant inlet port bypass passage

20: Second refrigerant outlet port bypass passage

21: Active inlet port

22: Active outlet port

23: Passive inlet port

24: Passive outlet port

25: Inlet nozzle

30: Lower distribution passage

31: Heat exchange passage

32: Upper distribution passage

33: Lower horizontal passage

34: Upper horizontal passage

35: Lower distribution path

36: Lower distribution path

37: Upper distribution path

38: Water bypass passage

39: Water bypass passage

40: Water bypass passage

41: Water bypass passage

42: Water inlet port

43: Water outlet port

50: Lower distribution passage

51: Heat exchange passage

52: Upper distribution passage

53: Lower horizontal passage

54: Upper horizontal passage

55: Lower distribution path

56: Lower distribution path

57: Upper distribution path

58: First refrigerant inlet port bypass passage

59: Second refrigerant inlet port bypass passage

60: First refrigerant outlet port bypass passage

61: Passive inlet port

62: Passive outlet port

63: Active inlet port

64: Active outlet port

65: Inlet nozzle

101: First heat exchanger plate

102: Lower distribution area

103: Heat exchange area

104: Upper distribution area

105: Vertical axis

106: Horizontal axis

107: First refrigerant inlet port hole

108: First refrigerant outlet port hole

109: Second refrigerant inlet port hole

110: Second refrigerant outlet port hole

111: Water inlet port hole

112: Water outlet port hole

113: Sealing section

114: Nozzle indentation

115: Bypass section

116: Sealing section

117: Bypass section

118: Lower distribution groove

119: Lower distribution groove

120: Upper distribution groove

121: Bypass section

122: Sealing section

123: Flat section

124: Lower water bypass section

125: Lower water bypass section

126: Upper water bypass section

127: Upper water bypass section

201: Second heat exchanger plate

202: Lower distribution area

203: Heat exchange area

204: Upper distribution area

205: Vertical axis

206: Horizontal axis

207: First refrigerant inlet port hole

208: First refrigerant outlet port hole

209: Second refrigerant inlet port hole

210: Second refrigerant outlet port hole

211: Water inlet port hole

212: Water outlet port hole

213: Sealing section

214: Nozzle indentation

215: Bypass section

216: Sealing section

217: Bypass section

218: Lower distribution groove

219: Lower distribution groove

220: Upper distribution groove

221: Bypass section

222: Sealing section

223: Flat section

224: Lower water bypass section

225: Lower water bypass section

226: Upper water bypass section

227: Upper water bypass section

301: Third heat exchanger plate

302: Lower distribution area

303: Heat exchange area

304: Upper distribution area

305: Vertical axis

306: Horizontal axis

307: First refrigerant inlet port hole

308: First refrigerant outlet port hole

309: Second refrigerant inlet port hole

310: Second refrigerant outlet port hole

311: Water inlet port hole

312: Water outlet port hole

313: Sealing section

314: Nozzle indentation

315: Bypass section

316: Sealing section

317: Bypass section

318: Lower distribution groove

319: Lower distribution groove

320: Upper distribution groove

321: Flat section

323: Bypass section

324: Lower water bypass section

325: Lower water bypass section

326: Upper water bypass section

327: Upper water bypass section

328: Sealing section

401: Fourth heat exchanger plate

402: Lower distribution area

403: Heat exchange area

404: Upper distribution area

405: Vertical axis

406: Horizontal axis

407: First refrigerant inlet port hole

408: First refrigerant outlet port hole

409: Second refrigerant inlet port hole

410: Second refrigerant outlet port hole

411: Water inlet port hole

412: Water outlet port hole

413: Sealing section

414: Nozzle indentation

415: Bypass section

416: Sealing section

417: Bypass section

418: Lower distribution groove

419: Lower distribution groove

420: Upper distribution groove

421: Flat section

423: Bypass section

424: Lower water bypass section

425: Lower water bypass section

426: Upper water bypass section

427: Upper water bypass section

428: Sealing section

1. A heat exchanger plate for use in a three circuit heat exchangerassembly, where the plate comprises a first distribution area havingthree port holes, a heat exchange area and a second distribution areahaving three port holes, where the plate comprises a corrugated patternhaving ridges valleys, wherein the central port hole of the firstdistribution area is positioned at a vertical distance from a firstshort end of the plate such that a fluid passage is obtainable betweenthe central port hole and the first short end of the plate when twoplates are stacked to form a fluid channel there between.
 2. The plateaccording to claim 1, wherein the central port hole of the seconddistribution area is positioned at a vertical distance from a secondshort end of the plate such that a fluid passage is obtainable betweenthe central port hole and the second short end of the plate when twoplates are stacked to form a fluid channel there between.
 3. The plateaccording to claim 1 or 2, wherein a port hole at a first corner of theplate is provided with a flat, ring-shaped bypass section adapted toform a refrigerant bypass passage around a port when two plates arestacked to form a refrigerant fluid channel between the plates.
 4. Theplate according to claim 3, wherein a water bypass section is providedat a second corner of the plate such that a water passage is obtainablebetween two adjacent bypass sections when two plates are stacked to forma water channel between the plates.
 5. The plate according to claim 1,wherein the first distribution area exhibits a chevron shape having afirst layout, the second distribution area exhibits a chevron shapehaving a second layout and where the heat exchange area exhibits achevron shape having a third layout, where the chevron shape of thefirst layout is directed in a first angular direction and the chevronshape of the second layout is directed in the opposite angulardirection.
 6. The plate according to claim 5, wherein the chevron shapeof the third layout is directed in the same angular direction as thechevron shape of the first layout.
 7. The plate according to claim 5,wherein the chevron shape of the third layout has more direction changesthan the first and the second layout.
 8. The plate according to claim 5,wherein the first and the second chevron shape resembles a V and thethird chevron shape resembles a W.
 9. The plate according to claim 1,wherein a lower distribution groove is provided between the firstdistribution area and the heat exchange area such that a lowerdistribution path is obtainable between two adjacent lower distributiongrooves when two plates are stacked to form a fluid channel between theplates.
 10. The plate according to claim wherein at least one of thelower distribution grooves comprises at least one restriction area suchthat a flow restriction is obtained in the lower distribution path. 11.The plate according to claim 9, wherein an upper distribution groove isprovided between the heat exchange area and the second distribution areasuch that an upper distribution path is obtainable between two adjacentupper distribution grooves when two plates are stacked to form a fluidchannel between the plates.
 12. A heat exchanger assembly, comprisingfour plates according to claim 1 or 2, wherein the first plate, thesecond plate, the third plate and the fourth plate differ from eachother.
 13. The heat exchanger assembly according to claim 12, where afirst refrigerant channel is provided between the first plate and thesecond plate, a water channel is provided between the second plate andthe third plate and a second refrigerant channel is provided between thethird plate and the fourth plate, and where each fluid channel comprisesa first distribution passage provided between two adjacent firstdistribution areas, a heat exchange passage provided between twoadjacent heat exchange areas and a second distribution passage providedbetween two adjacent second distribution areas, wherein a horizontalpassage is provided in the first distribution passage between thecentral water port and the neighbouring short end of the assembly. 14.The heat exchanger assembly according to claim 12, wherein a horizontalpassage is provided in the second distribution passage between thecentral water port and the neighbouring short end of the assembly. 15.The heat exchanger assembly according to claim 12, wherein a waterbypass passage is provided in a water distribution passage between arefrigerant port and a corner of the assembly.
 16. The heat exchangerassembly according to claim 12, wherein a refrigerant bypass passage isprovided around a refrigerant port in a refrigerant distributionpassage.
 17. The heat exchanger assembly according to claim 12, whereinan active inlet port is provided with an inlet nozzle and a secondactive inlet port is provided with an inlet nozzle, where the angles ofthe inlet nozzles are between 0 and 180 degrees relative to a verticalaxis and where the inlet nozzles point towards the central vertical axisof the assembly.
 18. The heat exchanger assembly according to claim 17,wherein the angles of the inlet nozzles are between 90 and 150 degrees.19. The heat exchanger assembly according to claim 12, wherein a lowerdistribution path is provided between a lower distribution passage and aheat exchange passage.
 20. The heat exchanger assembly according toclaim 12, wherein an upper distribution path is provided between a heatexchange passage and an upper distribution passage.
 21. The heatexchanger assembly according to claim 12, wherein the heat exchangerplates are joined by gluing, soldering, brazing, bonding or welding. 22.A three-circuit heat exchanger, comprising a plurality of heat exchangerassemblies according to claim 12, and further comprising a front plateand a back plate.